Systems exist that integrate licensed wireless systems (LWSs) and unlicensed wireless systems (UWSs) and provide seamless transition between the two.
An LWS refers to public cellular telephone systems and/or Personal Communication Services (PCS) telephone systems, for example, providing service over a licensed spectrum. Such licenses are expensive as is the equipment used to support communications these licensed frequencies, and this expense is passed on to the user.
A UWS, on the other hand, may comprise, for example, a base station with a physical connection to a landline providing service to a handset using an unlicensed, free spectrum (e.g., approximately 2.4 GHz or 5 GHz). Thus, the user of a licensed wireless system pays relatively high fees for relatively low quality service. Systems that integrate an LWS and a UWS allow service to be provided through the UWS, when a user is within an unlicensed wireless service coverage area. The user receives the benefit of the relatively inexpensive, high quality communication service. If the user moves outside of the unlicensed wireless service coverage area, the same communication session can be maintained without interruption by transitioning to the LWS.
FIG. 1 illustrates a system that integrates an LWS and a UWS in accordance with the prior art. System 100, shown in FIG. 1, includes an LWS 110 and a UWS system 150. The LWS 110 typically includes a number of mobile switching centers (MSCs) 112a-112c. Each MSC 112 typically serves multiple base station controllers (BSCs) 114a-114c, each of which, in turn, serves multiple base station transceiver systems (BTSs) 116a-116c. The LWS 110 provides mobile wireless communications to individuals using wireless transceivers, shown for example as user terminal (UT) 118. Wireless transceivers (UTs) include cellular telephones, PCS telephones, wireless-enabled personal digital assistants, wireless modems, and the like. A typical UT may include a display, keypad, and a control circuit. The display may provide a visual indication to a user when the UT is within the service range of the LWS or the UWS, the keypad is used in a conventional manner, and the control circuit may be in the form of a processor, a hardwired circuit, a programmable logic device, an application specific integrated circuit, and the like.
As shown in FIG. 1, UWS 150 is connected to the LWS 110 through an unlicensed network controller (UNC) 154 (also referred to as an IP network controller (INC). The UNC 154 is connected to an MSC (e.g., MSC 112c) of the LWS 110. Instead of one or more BSCs, MSC 112c has the UNC 154 connected to it. The UNC 154 is connected through internet 155 to a plurality of internet access points (IAPB) 156a-156c. 
If UT 118 is within the service coverage area of the IAPB 156a-156c, the communication is routed over the higher quality/lower cost UWS 150. If the UT 118 is not within the service coverage area of the IAPB 156a-156c, the communication is routed over the lower quality/higher cost LWS 110.
The system 100 can handover a communication between the LWS and the UWS. That is, while a communication is in progress the communication can be handed over from routing on the LWS to routing on the UWS or vice versa. For example, a user may initiate a communication while moving from one location to another location, and this communication may be routed over the LWS. After arriving at a desired destination, the user may be within the service coverage area of an IAP. The communication is then handed over from routing on the LWS to routing on the UWS so that the user can take advantage of the higher quality/lower cost of the UWS.
Conventional LWSs can provide location-based services because each BTS of the system provides service coverage for a corresponding geographic location. Moreover, each BTS has a unique identification. For example, in a Global System for Mobile Communications (GSM) system, each cell has a unique cell identifier, known as a cell global identifier (CGI). The CGI is comprised of a mobile country code, a mobile network code, a location area code, and a cell ID. In addition there is an absolute radio frequency control mobile (ARFCM) and a base station identity code (BSIC). When a user initiates a communication, the system can determine the general geographic location of the user and can provide location-based services to the user. Such services may include the location of proximate businesses or services of interest to the user, or providing the user's location to emergency services (e.g., medical or automotive assistance).
To maintain the ability to provide such services, the system must be able to effect and monitor a handover from one cell (the area covered by a particular BTS) to another. Typically, to effect handover, information has to be communicated between different nodes within the system. Each MSC and each BSC of a typical LWS has implemented therein, a configuration database containing information about the other elements within the system that the MSC of BSC requires to effect handover. For example, each particular MSC must store the CGIs for all of the cells for which it provides service, as well as the CGIs for each cell for which service is provided by a neighboring MSC (i.e., an MSC which may handover a communication to the particular MSC).
For a typical LWS, this amount of data is manageable because the BTSs are static and are added to the system incrementally. This is not the case with the UWS portion of an integrated system. For the UWS, instead of one BTS providing access to the network for multiple (e.g., hundreds) of UTs, each UT accesses the network through a distinct IAP. Determining and storing identification information for such a large number of access points would be time-consuming and resource intensive. Therefore, the integrated LWS/UWS system in accordance with the prior art, assigns a single cell identifier to the UNC/INC and all of the access points (e.g., IAPs) of the UWS portion of the integrated system. This cell identifier is referred to as the UNC global CGI. In a sense, the entire UWS portion of the integrated system is viewed as a single cell of the network for identification purposes. The single cell identifier associated with the UWS is stored in all of the MSCs of the system. Therefore, communications initiated on the LWS can be handed over to the UWS using the same cell identifier.
This scheme, reduces the time and resources required to store identification information for multiple access points of the UWS on many different MSCs, however, the scheme does not allow for providing location-based services to users on the UWS. To address that issue, each IAP may be assigned a CGI based on geographic location (e.g., longitude and latitude) or some other criteria. The only MSC to store all of the CGI information of the IAPB of the UWS is an interface MSC that connects the LWS to the UWS (e.g., MSC 112c of system 100).
One disadvantage of such a scheme is in the context of a handed out communication (i.e., handed out from the UWS to the LWS). The disadvantage is that a handover request message from the source MSC (i.e., interface MSC) for a particular CGI will be rejected by the destination MSC of the LWS. This rejection is due to the fact that the destination MSC will not recognize the CGI of any given IAP of the UWS because the CGI information is not stored on the destination MSC.
Another disadvantage of the prior art scheme described is in the context of a handed in communication (i.e., handed in from an LWS to a UWS). The disadvantage here is that the destination MSC (i.e., the interface MSC) cannot determine to which particular IAP the communication being handed over from the source MSC of the LWS pertains. Thus, for a handed in communication, location-based services cannot be provided.